Vsync off

[Nerva]

I have the same problem but with a R9 290. No working solution so far.
The setting in Catalyst affects only OpenGL applications and Radeon Pro is not working properly with these newer GPUs.
I'm using the GPU integrated in the CPU. That one is older and works with Radeon Pro.

To those claiming V-Sync affects only frame rate: You are wrong.
The difference between 60 FPS V-Sync ON and 60 FPS V-Sync OFF is damn significant. To the point of the game being unplayable with the former option.

EDIT: If you don't manage to turn off V-Sync, try limiting your framerate to 59 FPS. It does reduce input lag a bit. (But it's still inferior to turning V-Sync off)